Test 1: lecture 7 ekg part 3 Flashcards
4 questions to ask about an EKG
- Is the rate fast or slow
- Is the rhythm regular or irregular?
- Is there a P wave for every QRS complex?
Is there a P wave in front of every QRS complex?
is there a QRS complex following every P wave? - Are the QRS complexes:
– Supraventricular
– Ventricular
NSR for dog
70-170 bpm
NSR for cats
120-240 bpm
what are some things that cause tachycardia
increased sympathetic tone
fever, anemia, heart failure, adrenergic medications, and anxiety
what are some things that cause sinus bradycardia
excessive vagal tone
sinus node pathology
what is respiratory sinus arrhythmia
increased HR during inhale
decreased HR during exhale
reguarly irregular
common in dogs- caused by increased vagal tone
goes way with exercise, atropine or high sympathetic tone (stress, HF)
what is an example of irregularly irregular
Afib
sinus arrest
inappropriately long PP interval
long pause can cause fainting
can diagnose with holter monitor
what kind of dogs get sick sinus syndrome
long pause cause fainting
schnauzers
symptoms of sinus arrest in cats
fainting or seizures
long pause in beats
what is an ectopic beat
beat that is started at somewhere other then sinus node
(something is wrong)
QRS without a P wave
the ventricle depolarize without atrial depolarization is a —
ectopy
QRS without a P wave
ventricular ectopic beat
QRS wide and wierd
conduction is slow from cell to cell cause it has to move through muscle cells instead of normal pathway
what will happen to QRS with a supraventricular ectopic beat
impulse starts above the ventricle: sinus node, atrium, AV node
P wave will look abnormal, but QRS normal cause it moves through normal pathway
what is a APC
atrial premature beat
supraventricular origin
ectopic beat that is caused by something other then sinus node firing- causes early beat
QRS looks normal
space from normal to APC is called P-P’
P’ may not be seen if too early, hidden by T wave of earlier beat
P-P’
space between P wave and Pwave of ectopic beat
if close together with normal QRS normally APC (atrial premature beat)
beat orginates above the ventricle
APC
atrial premature beat
supraventricular origin
normal looking QRS
P-P’ very short
A fib- undulating baseline
Absence of P waves
Supraventricular QRS-T morphology (narrow)
Irregularly irregular rhythm
three hallmarks of Atrial Fibrillation
Absence of P waves
Supraventricular QRS-T morphology(narrow)
Irregularly irregular rhythm
ventricular premature contraction (VPC)
short R-R interval
QRS wide and bizarre
no P wave
T wave looks weird
can be from his-purkinje system or from random ventricular myocardial cell
VPCs will cause
ventricular premature contraction (VPC)
short R-R interval
wide and bizarre QRS
no P wave
R on T phenomenon
VPCs that happen right after each other leads to ventricles not contracting properly→ will quiver
ventricular triplet can lead to ventricular fibrillation
no diastolic interval
normal followed by VPC
probably not causing issues
R on T phenomenon
PVC
ventricular triplet can lead to ventricular fibrillation
3 or more ventricular premature contractions in a row is called
ventricular tachycardia
can lead to fainting or Vfib
QRS wide and wierd
QRS slurs into T wave
P wave present,but no relationship to QRS- often can’t see, hidden by QRS complex
V tach
3 or more VPC in a row
QRS wide and wierd
QRS slurs into T wave
P present but hidden by QRS
can lead to fainting, if R on T can lead to Vfib
escape vs premature ectopic ventricular beat
premature: happens before normal R-R interval
escape: long cause then wierd QRS, ventriculars sense no atrial beat and secondary pacemakers will depolarize spontaneously
HR controlled by AV node will be
40-60 bpm
HR controlled by purkinje cells would be
20-40 bpm
escape beat
beat caused by ventricle when there is no signal from atrium to beat
causes wierd wide QRS
ventricular premature beat
beat with wide and wierd QRS before normal R-R interval
ventricular escape beat
happens later, beat started by ventricle when no beat from atrium
wierd and wide QRS
PVC every 3rd beat
premature ventricular contraction
wierd and wide QRS
PVCs moving into Vfib
lethal rhythm
1st degree AV block
slowed conduction: long PR interval
2nd degree AV block
intermittent failure of conduction: sometimes no QRS complex following P wave
wenckebach
3rd degree AV block
AV conduction is absent
P-waves are never followed by a QRS complex
ventricles depolarize from subsidiary pacemakers
1st degree AV block
Slowed conduction: PR interval prolonged
2nd degree AV block
Intermittent failure of conduction: sometimes no QRS complex following P-wave
type 1 wenckebach
3rd degree AV block
complete
AV conduction is absent
* P-waves are never followed by a QRS complex
* ventricles depolarize from subsidiary pacemakers
P waves just doing its own thing, no QRS after it
QRS that do show up are caused by ventricules, will be wierd and wide, but are needed to beat ventricles= do not stop with meds
what can causes arrhythmias
scar tissue(infracts/ischemia)
Disturbance of ionic homeostasis in myocytes (high K)
drugs, stress (adrenaline)
genetic defects in ion channels
– Genetic defects in gap junctions between cells allowing normal electrical conduction(boxers)
when to treat a patient with abnormal EKG
Hemodynamic compromise due to arrhythmia
→ reduced cardiac output
→clinical signs: fainting, exercise intoleracne, hypotension, hypothermic
Patients at significant risk for sudden death
→ with underlying heat disease
→ dilated cardiomyopathy (doberman), subarotic stenosis, hypertropic cardiomyopathy(Cats)
